A solid state drive (SSD) has nonvolatile memory which retains data stored in the nonvolatile memory notwithstanding a power loss to the storage drive. The non-volatile memory may be NAND-based flash memory.
A multi-level non-volatile memory stores more than one bit per cell. Multi-level NAND memory having four (4) possible voltage levels per cell, may represent two (2) bits of data per cell. NAND memory having eight (8) voltage levels per cell may be referred to as triple-level cell (TLC) memory and may represent three (3) bits of data per cell. NAND memory having sixteen (16) voltage levels per cell may be referred to as quad-level cell (QLC) memory and may represent four (4) bits of data per cell. Each of these memory types respond with differing read and write speeds which may affect performance for operations with a host computer.